1. Technical Field
This invention relates generally to automotive air conditioners, and more particularly to an automotive air conditioner provided with an inner/outer-air bi-level unit including a partitioning member that forms a first air passage to introduce passenger-compartment inner air and a second air passage to introduce passenger-compartment outer air.
2. Discussion
In a conventional automotive air conditioner, the temperature of engine coolant water supplied to a heat exchanger does not rise sufficiently during winter. This condition is due largely to a drop in engine generated-heat as a result of the improvement in automotive fuel-consumption performance. Therefore, heating capacity within a passenger compartment becomes insufficient, and adequate heating is not obtained.
To avoid the above-described condition, one type of conventional an automotive air conditioner is provided with an inner/outer-air bi-level unit. The air conditioner ducts already-warmed passenger-compartment inner air to a first inner air passage, re-heats the inner air with a heat exchanger for heating use, and thereafter blows the inner air into the passenger compartment from a foot vent. The air conditioner also ducts low-humidity outer air to within a second outer air passage partitioned from the first air passage, reheats the outer air with the heat exchanger, and thereafter blows the outer air into the passenger compartment from a defroster vent when a vent mode is a foot mode or a foot-defroster mode.
This inner/outer-air bi-level unit also includes first and second air-mixing doors to regulate the quantity of air passing through the heat exchanger and the quantity of air bypassing the heat exchanger in each of the first and second air passages. An inner-air foot door is disposed in a passage communicating the first air passage and the foot vent, and opens the communicating passage when conditioned air is blown from the foot vent. This inner-air foot door is structured to open fully only when the vent mode of the inner/outer-air bi-level unit is an inner/outer-air bi-level mode, and to close fully during other outer-air induction modes or inner-air recirculation modes.
However, the above-proposed inner/outer-air bi-level configuration requires an actuator such as a servomotor to rotate the first and second air-mixing doors and an actuator such as a servomotor to rotate the inner-air foot door. Because of this, the number of door actuators becomes large, and control use wiring layout complexity and product cost increases.
To reduce product cost, the first and second air-mixing doors and the inner-air foot door may be interlocked with one actuator to drive the doors. In this case, when the first and second air-mixing doors begin to open, the inner-air foot door also begins to open, irrespectively of what the vent mode may be, and so conditioned air leaks from the foot vent even during a vent mode where conditioned air from the foot mode is unnecessary (for example the face mode or the defroster mode), which a rider may misinterpret as air conditioner breakdown or faulty operation.
In a case such as the foregoing where a single actuator is mechanically interlocked with the first and second air-mixing doors and the inner-air foot door, delaying the timing with which the inner-air foot door begins to open beyond the timing with which the first and second air-mixing doors begin to open may be considered.
However, when the outside temperature is moderate, such as in the spring or autumn, or when the temperature of the engine coolant water supplied to the heat exchanger is a predetermined temperature (for example 60.degree. C.) or less (in the interval until the predetermined coolant-water temperature is reached after starting the engine), the first and second air-mixing doors assume a fully open state (the so-termed MAX HOT position) even when the vent mode is the face mode. Because of this, leakage of conditioned air from the foot vent cannot necessarily be prevented, even when the timing with which the inner-air foot door begins to open is delayed beyond the timing with which the first and second air-mixing doors begin to open.